Each day, a myriad of metal and plastic parts of a variety of predetermined shapes are manufactured, such as by a forging process in which a permanent change in the shape of the part occurs. These parts are oftentimes manufactured in large quantities and are used in many different applications. For example, a number of tools, such as drill bits, screwdriver bits, router bits, percussion bits and jigsaw and reciprocating saw blades, are produced in mass quantities every day. Likewise, a number of other parts, such as fasteners, impact wrench anvils, coil and ballpoint chisels, gears, shafts, equalizer beams and actuator rods, are also manufactured in large quantities every day.
Accordingly, a number of manufacturing processes have been developed to form parts of a predetermined shape in large numbers. These manufacturing processes generally include a number of independent operations or steps which are performed in a predetermined sequence in order to create parts of the desired shape. For example, typical processes for manufacturing metal parts generally include forging operations, trimming operations, heat-treating operations and grinding and other finishing operations.
These manufacturing processes are typically designed to form a number of discrete workpieces into respective parts of a predetermined shape. Thus, these conventional manufacturing processes generally include an initial step of providing a number of discrete workpieces of the desired size and length. For example, a metal wire or rod can be cut into a number of discrete pieces prior to beginning the actual manufacturing process. Thereafter, the plurality of discrete workpieces are individually processed in order to create a plurality of parts of the predetermined shape.
As a result, each discrete part must generally be collected following every operation of these conventional manufacturing processes such that the part can be transported to the next stage or operation of the manufacturing process. In addition, since the parts must generally be aligned in a predetermined manner during each operation of these manufacturing processes, each part must generally be individually oriented prior to each next stage of the manufacturing process. Thus, even though parts are generally collected and transported between stages of these manufacturing processes in batches, these conventional manufacturing processes still generally require extensive handling of the parts in order to collect, transport and properly orient the parts between each stage of these manufacturing processes. These conventional manufacturing processes also typically require a relatively large number of parts to be in process at all times due to the batch-type processing. As will be apparent, the time and labor required to collect, transport and properly orient parts during these conventional manufacturing processes decreases the efficiency with which these parts are fabricated and, correspondingly, increases the cost of the resulting parts.
The inefficiencies created by handling and processing a plurality of discrete parts and the increased costs of maintaining a relatively large number of partially formed parts in process are particularly significant for those manufacturing processes which are designed to produce a large number of parts each day, such as tens of thousands, if not hundreds of thousands, of parts each day. For example, conventional manufacturing processes which produce metallic parts, such as drill bits, router bits, fasteners, percussion bits, jig saw and reciprocating saw blades, impact wrench anvils, coil and ballpoint chisels, gears, shafts, screwdriver bits, equalizer beams and actuator rods, generally produce parts at rates up to thousands or more per day.
In order to demonstrate the inherent inefficiencies of these conventional manufacturing processes which individually process a large number of discrete parts, the manufacturing process employed to form spade-type boring bits (hereinafter referred to as "spade-bits") is described hereinafter. Spade bits are typically formed by a hot forging process. According to this process, a coil of wire stock of a given diameter is cut into pieces, each of which is approximately the length of an individual spade bit. Each piece is then headed to form a portion of material with an increased diameter at the first end of the segment, i.e., a bulb of material having an increased diameter over a shorter length at the first end. Either during this initial heated process or following further heating of the bulb of material, the part is forged by compressing the heated bulb of material between a pair of opposed dies. Typically, the pair of opposed dies are closed in a rectilinear manner such that the heated bulb of material is subjected to compressive forces which displace the material into the predetermined fixed boundary shape defined by the dies. The forged part can then be trimmed and finished to produce spade bits such as those described above. An identification mark can also be stamped on the spade bit during its processing.
By initially cutting the wire stock and/or billets into a number of discrete pieces, however, the parts must be individually handled and processed throughout the hot forging process, thereby decreasing the efficiency with which the spade bits are fabricated and, correspondingly, increasing the resulting costs of the spade bits. For example, each individual part must be collected following each stage of the fabrication process and transported to the next stage. In addition, each individual part must be appropriately aligned during each step of the process to ensure that the input shape of the part serves as a proper and admissible preform to satisfy the requirement of each subsequent die operation, including die fill, such that the resulting spade bits meet the desired product tolerances.